C调用Fortran子例程时gcc链接出现__gfortran_st_close未定义符号如何解决

你遇到的报错信息如下：

Undefined symbols for architecture x86_64:
  "__gfortran_st_close", referenced from:
  "__gfortran_st_open", referenced from:
  "__gfortran_st_read", referenced from:
  "__gfortran_st_read_done", referenced from:
  "__gfortran_st_rewind", referenced from:
  "__gfortran_st_write", referenced from:
  "__gfortran_st_write_done", referenced from:
  "__gfortran_stop_string", referenced from:
  "__gfortran_transfer_array", referenced from:
  "__gfortran_transfer_character_write", referenced from:
  "__gfortran_transfer_real", referenced from:
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

以上所有__gfortran_开头的缺失符号都属于GNU Fortran运行时库libgfortran，你用gcc做链接时没有主动关联该库，才会触发该错误。

解决方法 #

• 方法1：链接阶段添加-lgfortran参数
  原有链接命令格式如下：

  gcc c_main.o fortran_sub.o -o target_program
  

  调整后：

  gcc c_main.o fortran_sub.o -o target_program -lgfortran
  

• 方法2：添加库路径后再链接
  如果执行方法1后仍然提示找不到库，说明gcc没有搜索到libgfortran的安装位置，先找到libgfortran.so（Linux）或libgfortran.dylib（macOS）的所在路径，用-L参数指定路径后再链接，示例：

  gcc c_main.o fortran_sub.o -o target_program -L/path/to/your/gfortran/lib -lgfortran
  

• 方法3：直接用gfortran执行链接步骤
  gfortran会自动加载Fortran运行时库依赖，无需手动指定参数，命令如下：

  gfortran c_main.o fortran_sub.o -o target_program
  

注意事项 #

你当前环境的gcc实际是clang伪装版本（报错末尾有clang标识），需要确保安装的gfortran架构与当前系统架构匹配，x86_64架构不要安装ARM版本的gfortran工具链，否则仍然会提示架构不匹配的符号缺失错误。

内容的提问来源于stack exchange，提问作者Grateful_for_stackoverflow